Browsing by Autor "Yvonne Y. Martinez"

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Efectos de los árboles exóticos y del ambiente materno sobre la producción de semillas, la germinación y el crecimiento inicial de Polylepis subtusalbida (Rosaceae) en el Parque Nacional Tunari, Bolivia
(2018) Edgar E. Gareca; Yvonne Y. Martinez; Claudia Solís; Luís F. Aguirre
Polylepis subtusalbida’s woodlands at the Southern slope of Parque Nacional Tunari (Cochabamba, Bolivia) are key native vegetation remnants between 3200-3900 m; they provide ecosystem services, specially to the city of Cochabamba. However, these woodlands are highly fragmented and coexist with exotic trees (Pinus radiata and Eucalyptus globulus). This work shows the effects of the exotic trees and the maternal environment on seed production, germination and initial growth of Polylepis. Three settings for the exotic trees were studied: Polylepis woodlands a) surrounded by semi-natural grassland, b) surrounded by exotic trees and c) mixed with exotic trees. Fruits from 67 mother trees belonging to seven fragments were used. The percentage of fruits with full seeds was measured as an estimation of seed production. Germination and early growth were evaluated in a common garden with a complete randomized design (germination) and a complete randomized block design (early growth). Variables from the maternal environment were reduced via PCA and backward multiple regression followed by general mixed linear models which were performed to evaluate the effect of the exotic trees, maternal traits and maternal microsite on the seed production, germination and early growth. The percentage of fruits with full seeds diminished as bare soil under the maternal tree increased. Germination was high and it was not affected by the studied factors. Early growth of the progeny was affected by the presence of the exotic trees, bare soil, leaf cover and health of the maternal tree. Seed production was identified as a limiting stage for Polylepis regeneration, and the exotic trees and maternal environment affected early growth of the progeny in a common garden (maternal effects).https://doi.org/10.25260/EA.18.28.1.1.698
Good news for habitat restoration projects: <i>Eucalyptus</i> does not inhibit the germination of <i>Polylepis</i>
(Wiley, 2022) Lidia Meneses; Yvonne Y. Martinez; Alexandre Antonelli; Edgar E. Gareca
Eucalyptus plantations outside their native range—either as an income source or aimed at sequestering atmospheric carbon to combat climate change—are increasingly known to reduce local biodiversity and groundwater levels, and to increase soil degradation and erosion. One additional but less understood effect of Eucalyptus on native floras is allelopathy—the chemical inhibition of other plants' germination. Here we investigate the putative allelopathic effects of Eucalyptus globulus on the germination of Polylepis subtusalbida , a keystone species that characterizes a species‐rich and highly threatened woodland habitat in the Bolivian Andes. We carry out controlled greenhouse experiments reflecting local rainfall, field litter quantity, and Eucalyptus leachate concentrations at multiple levels. Our results, based on five replicates with 390 Polylepis seeds each, show that contrary to our expectation Eucalyptus leachates does not affect germination significantly. Our findings suggest that projects aiming to remove Eucalyptus to restore Polylepis woodlands are likely to succeed even without the resource‐consuming removal of leaf litter, and potentially also bark and roots, from the ground after tree felling.
Regeneration patterns of Polylepis subtusalbida growing with the exotic trees Pinus radiata and Eucalyptus globulus at Parque Nacional Tunari, Bolivia
(Springer Science+Business Media, 2007) Edgar E. Gareca; Yvonne Y. Martinez; Ramiro O. Bustamante; Luís F. Aguirre; Melicio M. Siles